The present invention relates to the fields of automated manufacturing, and, more particularly, to an apparatus for attaching a strand of material, cord or wire to one or more pieces of material at high-speed.
The attachment of a strand of cord, thread, wire or other material to one or more pieces of material presents challenges to today""s high speed manufacturing processes. As an example, consider the tampon industry. The rate at which the product is consumed requires that a high speed manufacturing process be employed. Current tampon designs employ a withdrawal string, usually a cotton cord, to allow the user to remove the product after use. The cord must be firmly attached to the tampon pad, and must not shear the product or leave material behind upon withdrawal.
One current method for attaching a cord to a pad involves sewing the cord to the pad, although this technique has a variety of disadvantages. The piercing of a cord by the thread actually weakens the cord, thereby requiring a thicker cord to meet any strength specifications. The use of thread to attach a cord to a pad introduces the possibility of thread breakage or jamming of the sewing apparatus. Current high speed industrial sewing machines operate at rates that are typically insufficient to feed a subsequent high speed production line. As a result, multiple sewing stations are required and their respective outputs must be merged to feed a single production line. Such multiple stations operating near their maximum rated speed, as well as the merging mechanism, increase possibility and frequency of mechanical failures, jams, etc. Further, the reciprocating motion of traditional sewing machine movement, combined with the very thin and flexible handling qualities of thread, further increase the likelihood of jams, or mechanical failure.
Another method of attaching a cord to a pad involves punching of a cord once through the pad, and entanglement of the cord about the pad, i.e. with a knot or other restraining mechanism. Punching a cord once through a pad suffers from a lack of redundancy of attachment. Should the cord fail to puncture the pad, the needle fail to feed the cord properly, or the pad mis-aligned, the cord will not be attached to the pad. Also, the force on the cord during the use of the product assembly is undesirably concentrated at the single point where the cord is attached to the pad.
Cord entanglement does not offer the mechanical strength or integrity offered by a cord that is firmly attached to the pad since the cord can slip off. Simply tying a string to a pad in such a fashion creates a product which is prone to failure.
Accordingly, a need exists for a cord attachment mechanism that is fast enough to support a subsequent high speed production line and which meets the reliability requirements of its users.
The present invention discloses an article of manufacture and a method and apparatus for manufacturing the same. Specifically, an apparatus and method for attaching a cord to a piece of receiving material at high speeds comprises one or more pins which engage the cord, pierce the receiving material and draw the cord through the receiving material from the first side to a second side thereof so that at least one open loop is formed in the cord on the second side of the receiving material. The apparatus further comprises a shuttle mechanism which moves relative to the pin and engages an end portion of the cord drawing the cord through the open loop so as to complete the lacing stitch of the cord through the receiving material. The pin(s) may be implemented as a push pin and a spreader pin pair, movably mounted relative to each other, each of which are adapted to grasp the cord and penetrate the receiving material. The loop on the second side of the receiving material is formed as the push pin and spreader pin move relative to each other.
According to a first aspect of the invention, an article of manufacture comprises a piece of receiving material having first and second sides. A cord penetrates the receiving material at a location on the first side thereof and extends through the receiving material to a second side and therebeyond to form an open loop at the second side of the receiving material. The cord extends back through the receiving material from the second side thereof to the first side of the receiving material portion. A locking cord extends through the open loop formed on the second side of the receiving material. In alternative embodiments, a first end portion of the cord comprises the locking cord and may either penetrate the receiving material prior to extending through the open loop or may extend along the exterior surface of the receiving material prior to entering the open loop on the second side.
According to a second aspect of the invention, a method for attaching a cord to a piece of receiving material comprises the steps of: (a) engaging a portion of the cord; (b) drawing the cord through the receiving material from a first side of the receiving material through to a second side of the receiving material and therebeyond to form an open loop at the second side of the receiving material; and (c) threading a locking cord through the open loop formed on the second side of the receiving material. In an alternative embodiment, the method further comprises the step of eliminating any slack in the open loop.
According to a third aspect of the present invention, an apparatus comprises a frame, at least one pin movably mounted to the frame and adapted to penetrate a piece of receiving material and to draw a flexible cord from a first side of the receiving material through to a second side of the receiving material so as to form an open loop in the cord on the second side of the receiving material. The apparatus further comprises a shuttle having a first end adapted to receive a portion of the cord and to draw the portion of the cord through the open loop on the second side of the receiving material. In an alternative embodiment, the apparatus comprises a plurality of such pins. In another alternative embodiment, the shuttle is not mounted to the frame but the pin or pins are selectively movable relative to the shuttle.
In accordance with a fourth aspect of the invention, an apparatus for attaching a flexible cord to an article comprises a cord supply assembly, an article supply assembly, a loop forming assembly adapted to grasp the cord and to pass the cord through the article from a first side of the article to a second side of the article and to form an open loop with the cord on the second side of the article. The apparatus further comprises a shuttle having a first end adapted to receive a portion of the cord and to draw the portion of the cord through the open loop formed on the second side of the article. In accordance with an alternative embodiment, the loop forming assembly comprises a push pin and spreader pin pair movably mounted and having first ends adapted to receive the cord and to penetrate the article. The loop is formed on the second side of the article when the spreader pin moves relative to the push pin. In another alternative embodiment, the apparatus comprises a plurality of such push pin and spreader pin pairs. In such embodiment, multiple loops are formed on the second side of the article when the spreader pin pairs moves relative to the push pins. In yet another embodiment, the shuttle further comprises an edge portion selectively engagable to move the loop forming assembly relative to the shuttle so that the shuttle draws the portion of the cord through the open loop formed on the second side of the article in response to movement of the loop forming assembly relative to the shuttle.